Negative resistances are used to compensate for line losses, such as impedance converters, as described in "Der Transistor" by J. Dosse, Oldenbourg Verlag 1959, p. 220. A negative resistance can be implemented with a negative-feedback operational amplifier whose output is connected via resistors to its two inputs. The terminals of the negative resistance are the two inputs of the operational amplifier.
This type of circuit normally has an unsymmetrical structure and unsymmetrical properties. It is open-circuit stable as seen from the inverting input of the operational amplifier, and short-circuit stable as seen from the non-inverting input.
In some applications these asymmetries are undesirable, such as for the compensation of a resistance in both directions in a symmetrical arrangement.